Fix build on NetBSD and Apple

Author: asomers

src/unistd.rs

@@ -828,6 +828,8 @@ pub fn mkstemp<P: ?Sized + NixPath>(template: &P) -> Result<(RawFd, PathBuf)> {
 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
 #[repr(i32)]
 pub enum PathconfVar {
+    #[cfg(any(target_os = "dragonfly", target_os = "freebsd", target_os = "linux",
+              target_os = "netbsd", target_os = "openbsd"))]
     FILESIZEBITS = libc::_PC_FILESIZEBITS,
     LINK_MAX = libc::_PC_LINK_MAX,
     MAX_CANON = libc::_PC_MAX_CANON,
@@ -1016,6 +1018,9 @@ _POSIX_RAW_SOCKETS = libc::_SC_RAW_SOCKETS,
           target_os="linux", target_os = "macos", target_os="netbsd",
           target_os="openbsd"))]
 _POSIX_READER_WRITER_LOCKS = libc::_SC_READER_WRITER_LOCKS,
+#[cfg(any(target_os = "android", target_os="dragonfly", target_os="freebsd",
+          target_os = "ios", target_os="linux", target_os = "macos",
+          target_os = "openbsd"))]
 _POSIX_REALTIME_SIGNALS = libc::_SC_REALTIME_SIGNALS,
 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
           target_os="linux", target_os = "macos", target_os="netbsd",
@@ -1162,6 +1167,9 @@ SEM_NSEMS_MAX = libc::_SC_SEM_NSEMS_MAX,
           target_os = "ios", target_os="linux", target_os = "macos",
           target_os="openbsd"))]
 SEM_VALUE_MAX = libc::_SC_SEM_VALUE_MAX,
+#[cfg(any(target_os = "android", target_os="dragonfly", target_os="freebsd",
+          target_os = "ios", target_os="linux", target_os = "macos",
+          target_os = "openbsd"))]
 SIGQUEUE_MAX = libc::_SC_SIGQUEUE_MAX,
 STREAM_MAX = libc::_SC_STREAM_MAX,
 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",